Around 2004, I started exploring the possibilities of feedback manipulation in live performance. One of the results was Tubes, a piece for two performers, pvc-pipes and digital signal processing. Apart from some concert fragments, I never published any video material from the many working sessions with Cathy van Eck. Here are some fragments from an early version of the piece, below is a compilation from later recording sessions. A full version can be found here. Please listen in stereo or with headphones!